BOUCH, SirThomas (1822–1880), civil engineer, the third son of William Bouch, a captain in the mercantile marine, was born in the village of Thursley, Cumberland, on 23 Feb. 1822. A lecture by his first teacher, Mr. Joseph Hannah, of Thursby, 'On the Raising of Water in Ancient and Modern Times,' made so great an impression on his mind that he at once commenced reading books on mechanics. His first entrance into business was in a mechanical engineering establishment at Liverpool. At the age of seventeen he engaged himself to Mr. Larmer, civil engineer, who was then constructing the Lancaster and Carlisle railway. Here he remained four years. In November 1844 he proceeded to Leeds, where he was employed for a short time under Mr. George Leather, M. Inst. C.E. Subsequently be was for four years one of the resident engineers on the Stockton and Darlington railway. In January 1849 he left Darlington and assumed the position of manager and engineer of the Edinburgh and Northern railway. This engagement first brought to his notice the inconvenient breaks in railway communication caused by the wide estuaries of the Forth and the Tay, the efforts to remedy which afterwards occupied so much of his attention. His proposal was to cross the estuaries by convenient steam ferries, and be prepared and carried into effect plans for a 'floating railway'—a system for shipping goods trains which has ever since been in operation. Soon after completing this work Bouch left the service of the Northern railway and engaged in general engineering business. He designed and carried out nearly three hundred miles of railways in the north of England and Scotland, the chief of these being the South Durham and Lancashire Union, fifty miles long, and the Peebles, ten miles long, the latter being considered the pattern of a cheaply constructed line. On the introduction of the tramway system he was extensively engaged in laving out lines, including some of the London tramways, the Edinburgh, Glasgow, and Dundee tramways, and many others. In the course of his professional work Bouch constructed a number of remarkable bridges, chiefly in connection with railways. At Newcastle-on-Tyne he designed the Redheugh viaduct, a compound or stiffened-suspension bridge of four spans, two of 260 feet and two of 240 feet each. In his principal railway bridges, independent of the Tay bridge, were the Deepdale and Beelah viaduct on the South Durham and Lancashire railway, the Bilston Burn bridge on the Edinburgh, Loanhead, and Roslin line, and a bridge over the Esk near Montrose. In all these bridges the lattice girder was used, because of its simplicity and its slight resistance to the wind encountered at such high elevations.

In 1863 the first proposals for a Tay bridge were made public, but the act of parliament was not obtained until 1870. The Tay bridge, which crossed the estuary from Newport in Fife to the town of Dundee, was within a few yards of two miles long. It consisted of eighty-five spans—seventy-two in the shallow water, and thirteen over the fairway channel, two of these being 227 feet, and eleven 245 feet wide. The system of wrought-iron lattice girders was adopted throughout. After many delays the line was completed from shore to shore on 22 Sept. 1877. The inspection of the work by Major-general Coote Synge Hutchinson, R.E., on behalf of the board of trade, occupied three days, and on 31 May 1878 the bridge was opened with much ceremony. The engineer was then presented with the freedom of the town of Dundee, and on 26 June 1879 he was knighted. The traffic was continued uninterruptedly till the evening of Sunday, 28 Dec. 1879, when during a violent hurricane the central portion of the bridge fell into the river Tay, carrying with it an entire train and its load of about seventy passengers, all of whom lost their lives. Under the shock and distress of mind caused by this catastrophe Bouch's health rapidly gave way, and he died at Moffat on 30 Oct. 1880. The rebuilding of the Forth bridge was begun in 1882. Bouch became an associate of the Institution of Civil Engineers on 3 Dec. 1850, and was advanced to the class of member on 11 May 1858. He married, July 1853, Miss Margaret Ada Nelson, who survived him with one son and two daughters. His brother, Mr. William Bouch, was long connected with the locomotive department of the Stockton and Darlington and North Eastern lines.

[Minutes of Proceedings of the Institution of Civil Engineers, lxiii. 301-8 (1881); Illustrated London News, with portrait, lxxvii. 468 (1880); Times, 29, 30, and 31 Dec. 1879; Report of the Court of Inquiry and Report of Mr. Rothery upon the Fall of a portion of the Tay Bridge, in Parliamentary Papers (1880), C 2616 and C 2616-i.]